Time-varying thermoelastic coupling analysis of heat source of ball screw feed drive system

Abstract

Abstract Friction heat generation of ball screw nut pair may lead to changes in the contact state between ball and raceway. Different contact states may result in a change in the intensity of the heat source of the nut pair, which in turn affects the contact state again until a certain balance is reached. At present, the time-varying research of the heat source of the screw nut pair is mainly carried out from the boundary conditions and the location of the heat source, without considering the influence of the internal structure change of ball screw nut pair. In order to fill this gap, a time-varying thermoelastic coupling analysis method for heat source of screw nut pair is proposed. In this paper, the contact model of ball and raceway is established by the elastic theory of plane strain, and the theoretical solution of the contact point displacement of ball raceway under thermal influence is derived by combining with the thermoelastic theory. Then, through the method of polygon equivalence of ball and raceway profile, the contact angle variation process of ball and raceway under the coupling effect of heat and structure was described geometrically, and the variation rule of heat source intensity was further obtained. In addition, the nut temperature variation rule was obtained through the temperature field experiment of the screw nut pair. The temperature variation curve of the nut pair under heat source induction in the actual working condition was fitted after the temperature drop data and the ambient temperature data were processed. By comparing the theoretical temperature variation curve under constant heat source induction, the heat source variation curve of the nut pair under the actual working condition was finally fitted. The correctness of the thermoelastic theory analysis is further verified. The method proposed in this paper analyzes the variation law of the heat source intensity from both theoretical and experimental perspectives, which has important reference significance for the study of the thermal characteristics of the ball screw system.